We propose a series of structured interviews and experimental studies intended to examine adolescents' perceptions regarding the risks of AIDS and alcohol consumption and to determine how these perceptions related to their risk behaviors. The research has two foci; (1) methods development, involving the evaluation of alternate methods for measuring and analyzing perceptions of risk probability, and (2) theory development, consisting of documentation and evaluation of adolescents' risk perceptions regarding AIDS. The intended results will have practical value, providing guidelines for intervention programs and further risk elicitation studies. The method development portion of our research will focus on identifying the (a) response mode best suited to eliciting quantitative measures of the perceived magnitude of AIDS risks and (b) the analytical methods best suited to analyze the data generated by that and other methods. In addition, these studies will evaluate the simultaneous and prospective relationship between judgments of one's own risk and self-reported risk behaviors. As part of theory development, we will address two major hypotheses regarding causes of adolescents AIDS-related behaviors, each having direct implications for interventions. The first is that teenagers misperceive the nature of AIDS risk (in which case they need ;more accurate knowledge). This study involves an open-ended elicitation of subjects mental models of the risk processes involved in alcohol use and HIV exposure and a comparison of these models to an expert model of these same processes. The second, which might be viewed as an extreme version of the first, is that teenagers believe that they are invulnerable to AIDS (suggesting the need for even more fundamental education). The proposed studies involve the three subject comparisons: (1) adult-adolescent age comparison (12-13 or 15-17 year old teens and their parents), (2) adolescent age comparison (12-13 year olds vs. 15-17 year olds), and (3) risk comparisons (adolescents who are low vs. high risk for HIV infection).